National Institute of Oceanography, India

About: National Institute of Oceanography, India is a facility organization based out in Panjim, Goa, India. It is known for research contribution in the topics: Monsoon & Population. The organization has 4713 authors who have published 6927 publications receiving 174272 citations.

New acetogenin peroxides from the Indian sponge Acarnus bicladotylota.

Abstract: Two new cyclic peroxides (1 and 2) and the known metabolite 3 have been found in the organic extract of the Indian sponge Acarnus bicladotylota. The structure of the new products has been assured by chemical and spectroscopic methods. The absolute stereochemistry of 1-3 has been determined by Mosher's method on the semisynthetic derivative 4.

Seasonal sea surface temperature contrast between the Holocene and last glacial period in the western Arabian Sea (Ocean Drilling Project Site 723A): Modulated by monsoon upwelling

Abstract: [1] Annual, summer, and winter sea surface temperatures (SSTs) in the western Arabian Sea were reconstructed through the last 22 kyr using artificial neural networks (ANNs) based on quantitative analyses of planktic foraminifera. Down-core SST estimates reveal that annual, summer, and winter SSTs were 2, 1.2, and 2.6°C cooler, respectively, during the last glacial period than in the Holocene. A 2.5°C SST increase during Termination 1A (hereinafter referred as glacial to Holocene transition) in the western Arabian Sea. The study reveals a strong seasonal SST contrast between winter and summer from 18 to 14 calendar kyr owing to the combined effect of weak upwelling and strong cold northeasterly winds. Minor or no seasonal SST changes were noticed within the Holocene period, which is attributed to the intense upwelling during the summer monsoon. This causes a lowering of SST to values similar to those of the winter season in analogy with the present day. A 3°C rise in winter SSTs during the glacial to Holocene transition coincides with a strengthening of the monsoon, suggesting a link between winter SST and monsoon initiation from the beginning of the Holocene. Strikingly, annual, summer, and winter SSTs show a cooling trend from ∼8 ka to the present day, implying tropical cooling in the late Holocene.

The Tectonic origin of the Bay of Bengal and Bangladesh

Abstract: We are able to decipher the tectonic evolution of the Bay of Bengal, a puzzle which has not been satisfactorily solved in the past, and we are also able to shed new light on origin of the buried 85°E Ridge. We do so by incorporating a number of disparate items into a unified solution. These items are the marine magnetic anomalies in the Western Basin of the Bay of Bengal, the Rajmahal and Sylhet traps, and Deep Seismic Sounding lines in India, a prominent magnetic anomaly doublet and seismic Seaward Dipping Reflectors in Bangladesh, and a new precise gravity map of the Bay of Bengal. We identify seafloor-spreading magnetic anomalies ranging in age from 132 Ma (M12n) to 120 Ma (M0) in the Western Basin. These anomalies are “one sided”; the conjugate anomalies lie in the Western Enderby Basin, off East Antarctica. The direction of spreading was approximately NW-SE, and the half-spreading rates varied from 2.5 to 4.0 cm/yr. With the arrival of the Kerguelen plume around M0 time, seafloor spreading was reorganized and a new spreading axis opened at or close to the line joining the Rajmahal and Sylhet traps. The prominent magnetic anomaly doublet connecting the Rajmahal and Sylhet traps indicates that these traps are not individual eruptions at about 118 Ma, but rather, together, define the new line of opening. Spreading started at this line, and subsequently, India changed direction from west to north. The new oceanic crust, thus generated, underlies Bangladesh and the Eastern Basin of the Bay of Bengal and is younger than 118 Ma. The western boundary of the new ocean floor is a transform fault, which was generated by the spreading axis jump. This transform fault appears as the 85°E Ridge, and further north, on land, as a negative free-air gravity anomaly strip. A unique feature of the northern boundary of the new oceanic crust is that due to the later deposition of enormous sediments derived from the Himalayan orogeny, it lies onshore Bangladesh, in contrast to most continent-ocean boundaries in the world, which lie offshore.